A disposable type syringe is generally provided for preventing a secondary infection of disease which occurs due to the reuse of a syringe. The reuse of a syringe is legally prohibited, so the syringe used once is subject to disposal as a waste. The disposable type syringe should be disposed with a cap being covered on the tip of a needle.
However, a user might be hurt by a needle when covering a cap on the tip of a needle in the course of disposal. In addition, a waste disposal worker might be hurt by a needle as a cap is disengaged from the tip of a needle in the course of disposal. A medical worker or a syringe waste disposal worker might be hurt by a needle which was used once, so the hurt worker might be infected by the blood of a patient. This kind of medical accident is frequently reported in the medical field.
In order to overcome the above problems, the applicant of the present invention has filed Korean utility model registration number 0391370 and Korean utility model registration number 0423645 in which the needle of a syringe used once is inputted into a cylinder for disposal as a waste.
According to the Korean utility model registration numbers 0391370 and 0423645, since a needle support is not accurately fixed to a plunger in the course that a needle is being inputted into a cylinder, so a needle is not fully inputted into a cylinder.
FIG. 1 is a cross sectional view of a conventional safety syringe and FIG. 2 is a partially enlarged view illustrating a state that a needle support is is caught by a plunger in a conventional safety syringe.
The conventional safety syringe comprises a needle support 5 which fixedly supports a needle 4 and is formed of a plurality of engaging legs 50 at a lower side of the same, with each engaging leg 50 being equipped with a first connector 51 and a second connector 52 at its lower side. The first connector 51 is fixed in contact with a first engaging shoulder 14 of an upper side of the cylinder 1 so that the needle support 5 is not inwardly pushed into the cylinder 1 in the course of use of a syringe. The second connector 52 is an engaging member for being fixedly caught by a needle support insertion member 24 of an upper side of a plunger 2 so that the needle 4 is inputted into the inner side of the cylinder 1 and is accommodated therein when disposing the cylinder after use.
Namely, a needle support insertion member 24 is formed at an upper side of the plunger 2 for receiving engaging legs 50, so that the engaging legs 50 of the needle support 5 are accommodated therein. A second engaging shoulder 24a is formed at an inner side of the needle support insertion member 24 and is fixedly engaged by a second connector 52 of a lower side of the engaging leg 50. When the plunger 2 moves backwards, the needle support 5 is pulled with the aid of an engagement between the second connector 52 and the second engaging shoulder 24a and is inputted into the inner side of the cylinder.
However, in the above conventional safety syringe, the second engaging shoulder 24a formed at an inner side of the needle support insertion member 24 is formed roughly, not formed accurately, so that it is impossible to obtain a stable engaging state with the second connector 52 formed at the needle support 5, whereby the engaged state is loosened and disengaged for thereby allowing the needle support 5 not to input into the interior of the cylinder.
The problems that the second engaging shoulder 24a formed at an inner side of the needle support insertion member 24 are formed roughly, not formed accurately is due to a design limit in the course of a molding process.
FIG. 3 is a view illustrating an example for describing a molding process for molding a conventional safety syringe and FIG. 4 is a view illustrating an example for describing the problems that a second engaging shoulder is formed roughly, not formed accurately in a conventional safety syringe.
In the molding process of a conventional safety syringe, a plastic liquid is injected into a mold A is solidified and the mold A is separated. According to the conventional safety syringe, the second engaging shoulder 24a at the inner side of the needle support insertion member 24 might be disadvantageously damaged or worn out while the mold A is being separated.
The damaged or worn-out second engaging shoulder 24a does not form a stable engaging relationship with the second connector 52, so that the needle support 5 is not reliably inputted into the inner side of the cylinder.